From one sentence to the sky · Step 6 of 15
Three directions
Four conditions give four directions a record can differ in. One is time. Three are space.
Up and down. Left and right. Forward and back. You have never been anywhere else. Not two directions. Not four. Three.
Physics measures three and builds on it. No accepted theory says where the three comes from.
Here it comes from the four conditions. Each gives one direction a record can differ in.
Record: what happened cannot unhappen. That direction has a forward and no back. That is time.
Constraint: a record is somewhere, not everywhere. Reaching anywhere else takes time, and the delay is distance.
Symmetry: two records at the same moment and the same distance can still sit on different sides. That is width.
Break: the break happens at a place, where the next record will be written. That is depth.
Four directions. One is time. Three remain. Those are space.
No condition can be built from the other three, so no direction can either. A fourth direction of space would need a fifth condition.
What it stands on
What it predicts
No fourth direction of space. Gravity keeps its inverse-square law at short range, and no collider finds an extra dimension.
What would kill it
A condition that gives no direction, or two. A fifth condition. A fourth direction of space, at a collider, or in gravity straying from its inverse-square law at short range.